Create API documentation

[mdpiper]

Although each function in AtomNeb-idl has a docstring describing its functionality, it's a best practice to create separate API documentation for a package. This makes it easier for developers (and users) to understand what each routine in the package does.

A recommendation: IDLdoc produces nice API documentation, and it's an accepted standard in the IDL community.

[mgalloy]

If you do this for the code in your examples directory as well, you can satisfy the documentation of real-world examples requirement as well.

[danehkar]

I created API documentation with IDLdoc and uploaded them to docs.